21683628689 has 2 divisors, whose sum is σ = 21683628690. Its totient is φ = 21683628688.

The previous prime is 21683628679. The next prime is 21683628721. The reversal of 21683628689 is 98682638612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16466022400 + 5217606289 = 128320^2 + 72233^2 .

It is a cyclic number.

It is not a de Polignac number, because 21683628689 - 2⁸ = 21683628433 is a prime.

It is not a weakly prime, because it can be changed into another prime (21683628679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10841814344 + 10841814345.

It is an arithmetic number, because the mean of its divisors is an integer number (10841814345).

Almost surely, 2^21683628689 is an apocalyptic number.

It is an amenable number.

21683628689 is a deficient number, since it is larger than the sum of its proper divisors (1).

21683628689 is an equidigital number, since it uses as much as digits as its factorization.

21683628689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11943936, while the sum is 59.

The spelling of 21683628689 in words is "twenty-one billion, six hundred eighty-three million, six hundred twenty-eight thousand, six hundred eighty-nine".